Mazdutide (IBI362) is a synthetic, fatty-acid-conjugated long-acting peptide developed by Innovent under licence from Eli Lilly as a dual agonist of the GLP-1 and glucagon receptors. Built on the natural oxyntomodulin scaffold — a gut hormone that engages both receptors at once — it pairs the appetite- and glucose-modulating effects of GLP-1 with the energy-expenditure and hepatic-lipid effects of glucagon signalling, making it one of the two leading GLP-1/glucagon dual agonists in metabolic research.
Mazdutide (IBI362 / LY3305677) is a once-weekly dual agonist of the GLP-1 and glucagon receptors — an oxyntomodulin analogue developed by Innovent under licence from Eli Lilly. In the Phase 3 GLORY-1 trial in Chinese adults with overweight or obesity (n=610), it produced ~14.3% mean body-weight reduction at 48 weeks at the 4 mg and 6 mg doses, with roughly 95% of participants on 6 mg achieving ≥30% liver-fat reduction and about 77% reaching normal liver fat. It has also been studied in type 2 diabetes through the DREAMS programme. Its differentiator versus GLP-1 mono-agonists is the glucagon arm, which is studied for raising energy expenditure and mobilising hepatic lipid. Mazdutide's first NDA for chronic weight management is under NMPA (China) review; it remains investigational elsewhere and is supplied as a compound for in vitro research use only — not approved for human use. Research-grade Mazdutide is available from RS Bio Labs in three strengths at ≥99% purity; see the buy Mazdutide UK page.
Mazdutide, known by its developer codes IBI362 and LY3305677, is a synthetic long-acting peptide engineered to activate two distinct metabolic receptors simultaneously: the glucagon-like peptide-1 receptor (GLP-1R) and the glucagon receptor (GCGR). Because it engages both, it is described in the literature as a "dual agonist" or "GLP-1/glucagon co-agonist", placing it one step beyond the single GLP-1 agonist Semaglutide while sitting alongside Survodutide as one of the two most-studied compounds in the GLP-1/glucagon class.
The compound is built on the scaffold of oxyntomodulin, a naturally occurring gut hormone that activates the GLP-1 and glucagon receptors together. The design idea is to reproduce that natural dual signalling in a molecule engineered for a long, once-weekly duration of action. The GLP-1 arm reduces energy intake (appetite suppression, slowed gastric emptying, glucose-dependent insulin secretion), while the glucagon arm is studied for its capacity to increase energy expenditure and mobilise hepatic lipid — a combination that has attracted particular attention for its effects on liver fat.
As of 2026 Mazdutide is an investigational compound: its first New Drug Application for chronic weight management is under review by China's National Medical Products Administration (NMPA), and it remains investigational in all other jurisdictions. RS Bio Labs supplies it strictly as a research reagent for in vitro laboratory work. Researchers looking to buy Mazdutide in the UK can obtain it in three strengths, each third-party HPLC tested to ≥99% purity.
Mazdutide originates from Eli Lilly's incretin-engineering programme, where it carried the code LY3305677. Development rights for Greater China were licensed to Innovent Biologics, which advanced the molecule under the code IBI362 and has driven its late-stage clinical programme. The scientific lineage runs from native oxyntomodulin — a gut hormone that engages both the GLP-1 and glucagon receptors but is degraded within minutes — to a fatty-acid-conjugated analogue engineered for a long, once-weekly duration of action.
The rationale for building on the oxyntomodulin scaffold is that nature already provides a single peptide that touches both receptors. Where GLP-1 mono-agonists act only on appetite and glucose-dependent insulin secretion, adding balanced glucagon-receptor activity is studied as a way of layering an energy-expenditure and hepatic-lipid effect on top of the familiar GLP-1 profile — while the GLP-1 arm offsets the glucose-raising tendency of unopposed glucagon signalling.
Innovent's clinical programme has progressed through Phase 1 and Phase 2 into pivotal Phase 3 studies. The Phase 2 randomised trial in Chinese adults with obesity established dose-dependent weight reduction and tolerability, setting the stage for the GLORY Phase 3 weight-management programme (including GLORY-1, ClinicalTrials.gov NCT05607680) and the DREAMS programme in type 2 diabetes. On the strength of these data, Innovent submitted Mazdutide's first NDA for chronic weight management to the NMPA.
Mazdutide is a single peptide molecule that binds and activates two structurally related class B G-protein-coupled receptors. Each sits at a different node of the energy-balance network, and the combined agonism produces a metabolic phenotype distinct from that of a selective GLP-1 agonist. Receptor affinity has been tuned across both targets to preserve metabolic synergy while limiting the glucose-raising tendency of unopposed glucagon signalling.
The glucagon arm is the crux of the design. In isolation, glucagon-receptor activation raises blood glucose — an undesirable effect. But when paired with potent GLP-1 activity, the insulin-promoting arm offsets that tendency, allowing the metabolic-rate and hepatic-lipid benefits of glucagon signalling to be harnessed while glycaemic control is maintained or improved. The molecule itself is a fatty-acid-conjugated long-acting peptide; the fatty-acid tail promotes reversible binding to serum albumin, which is what gives Mazdutide its extended, once-weekly duration of action. For a broader treatment of how these pathways differ, see our guide to GLP-1 vs GIP vs glucagon agonists.
Mazdutide's clinical evidence base spans obesity and type 2 diabetes, and is anchored by the pivotal Phase 3 GLORY-1 readout in Chinese adults with overweight or obesity. The headline results are summarised below, followed by the individual trial cards.
| Trial / population | Publication | n | Headline result |
|---|---|---|---|
| Phase 3 · Obesity (GLORY-1) | NEJM, 2025 | 610 | ~14.3% mean weight reduction at 48 wk (4 mg / 6 mg) |
| Phase 3 · Liver fat (GLORY-1 substudy) | NEJM, 2025 | 610 | ~95% on 6 mg with ≥30% liver-fat reduction; ~77% reached normal liver fat |
| Phase 2 · Obesity (Chinese adults) | PubMed, 2023 | — | Dose-dependent weight reduction; tolerability consistent with the incretin class |
Mazdutide's defining pharmacokinetic feature is a duration of action long enough to support once-weekly administration. This is a direct consequence of the molecule's fatty-acid conjugation, which drives reversible binding to serum albumin. Albumin binding acts as a circulating reservoir, slows renal clearance, and shields the peptide from rapid proteolytic degradation — the same design principle used across the modern long-acting incretin class.
A once-weekly schedule means plasma concentrations accumulate over successive administrations and approach steady state after roughly four to five weeks. This accumulation behaviour is the reason published protocols use gradual dose escalation: titrating upward over several weeks allows tolerance to the gastrointestinal effects to develop as concentrations rise. For a broader mechanistic treatment, see our guide to GLP-1 vs GIP vs glucagon agonists.
| Parameter | Value (approx.) | Note |
|---|---|---|
| Duration of action | Weekly | Fatty-acid/albumin driven |
| Research schedule | Once weekly | Long-acting analogue |
| Time to steady state | ~4–5 weeks | Accumulation over dosing |
| Class | Oxyntomodulin analogue | Dual GLP-1 / glucagon |
| Elimination | Proteolysis + renal | Slowed by albumin binding |
As a lyophilised (freeze-dried) powder, Mazdutide is highly stable. Removing water from the formulation dramatically slows the chemical degradation pathways — hydrolysis, deamidation, oxidation and aggregation — that shorten a peptide's shelf life in solution. Sealed, protected from light and kept cool, lyophilised Mazdutide retains its integrity over long periods.
Stability falls once the powder is reconstituted. In solution the peptide becomes susceptible to gradual hydrolysis and to physical stresses such as agitation (which can cause aggregation and foaming) and repeated freeze–thaw cycles (which mechanically damage peptide structure). Heat and light accelerate degradation in both states. In practical terms this means the lyophilised vial is the storage-stable form, and the reconstituted solution should be treated as a shorter-lived working stock — see Storage and Reconstitution below.
Correct storage preserves both the mass and the biological integrity of the compound. The guidance below reflects standard best practice for lyophilised research peptides.
| State | Temperature | Approx. shelf life | Notes |
|---|---|---|---|
| Lyophilised | −20 °C (freezer) | Months to years | Best long-term option; protect from light |
| Lyophilised | 2–8 °C (fridge) | Weeks to months | Fine for medium-term storage |
| Lyophilised | Room temperature | Days (transit) | Tolerates brief shipping periods |
| Reconstituted | 2–8 °C (fridge) | ~4–6 weeks | Bacteriostatic water aids stability; keep dark |
| Reconstituted | Frozen | Avoid | Freeze–thaw degrades the peptide |
Label reconstituted vials with the date of preparation, minimise exposure to light and heat, and avoid repeatedly warming and cooling a working stock. Allow refrigerated vials to return toward room temperature before handling to reduce condensation.
The following describes standard laboratory technique for preparing a research stock solution from a lyophilised vial. It is not guidance for human use of any kind.
Reconstitution simply means dissolving the freeze-dried powder into solution. The standard diluent for a multi-use research vial is bacteriostatic water (water with 0.9% benzyl alcohol, which suppresses microbial growth). You will also need a sterile syringe and alcohol wipes. Technique matters: wipe the vial stopper, draw the chosen volume of bacteriostatic water, and add it slowly down the inner glass wall rather than squirting it directly onto the powder. Let the peptide dissolve, swirl gently, and never shake — agitation causes foaming and can damage the peptide.
Concentration is simply the mass of peptide divided by the volume of water added. Adding more water gives a lower concentration:
| Vial | Bacteriostatic water added | Resulting concentration |
|---|---|---|
| 5 mg | 1 ml | 5 mg/ml |
| 5 mg | 2 ml | 2.5 mg/ml |
| 10 mg | 1 ml | 10 mg/ml |
| 10 mg | 2 ml | 5 mg/ml |
| 15 mg | 3 ml | 5 mg/ml |
Once reconstituted, store the vial refrigerated at 2–8 °C and use it within a few weeks (see Storage). Maintain sterility throughout and label the vial with the concentration and preparation date.
Mazdutide sits on the GLP-1/glucagon rung of the incretin "agonism ladder." The table below places it against the other most-studied metabolic research peptides by receptor targets and headline trial effect. Note that Mazdutide and Survodutide are the two leading GLP-1/glucagon dual agonists, distinct from the GIP-containing dual and triple agonists. For the mechanistic detail behind these classes, see GLP-1 vs GIP vs glucagon.
| Compound | Receptor targets | Class | Peak trial weight change | Half-life |
|---|---|---|---|---|
| Mazdutide | GLP-1 + Glucagon | Dual | ~14.3% (Ph3, 48 wk) | Weekly |
| Survodutide | GLP-1 + Glucagon | Dual | MASH-focused Ph2 | ~6 days |
| Retatrutide | GIP + GLP-1 + Glucagon | Triple | ~24.2% (Ph2, 48 wk) | ~6 days |
| Tirzepatide | GIP + GLP-1 | Dual | ~22.5% (Ph3, 72 wk) | ~5 days |
| Semaglutide | GLP-1 | Mono | ~15% (Ph3, 68 wk) | ~7 days |
The pattern across the class is that engaging more complementary receptor systems tends to raise the ceiling on effect size. Mazdutide and Survodutide occupy the GLP-1/glucagon niche — pairing appetite suppression with the glucagon "energy-out" and hepatic-lipid arm — while the GIP-containing dual and triple agonists sit higher on the reported weight-change scale. To compare live pricing and strengths, see the buy Mazdutide UK and buy Retatrutide UK pages.
The findings above are drawn from the following peer-reviewed publications and trial registrations. Links open on the publisher or registry site.